1. Field of the Invention
This invention relates to augmented vision systems, and more particularly to a front view mirror system particularly adapted for vehicles in which an operator is so positioned that he has no direct "line of sight" access to a field of view which is essential to success of his operating function.
2. Description of the Related Art
Modern high speed hypersonic aircraft and transatmospheric space vehicles depend in large part on transparencies for visual cues to the craft commanders charged with piloting the vehicles to conventional runway landings. Streamlining of these crafts' mold lines calls for shallow impact angles on external surfaces and minimal disturbances to flow lines for efficient flight in the atmosphere. This feature of long shallow surfaces and minimal flow line disturbance would require large areas of conventional transparencies for even marginal line of sight access by the pilot to runway surfaces and navigation aides such as beacons and strobed cues. Transparencies are heavier and bulkier than the stronger composites or special high temperature metals used for craft structure and they are less able to contain harmful radiation and reject thermal energy than conventional structural materials. Long, sloping areas necessary to preserve streamlines for forward facing transparencies also compromise optical quality of presentations to crew members.
Under constraints of minimizing weight and preserving stream lines, providing a pilot with "out-the-window" vision has become a major design criterion for modern hypersonic aircraft. The current Concorde supersonic transport provides such visibility to its crew through a "droop-nose" arrangement whereby the nose section, forward of the cockpit and flight crew, is hinged downward during its low speed takeoff and landing operations. Rockwell International's XB-70 incorporated a long windshield ramp covering its main forward transparency to preserve streamlines and provide the necessary line-of-sight access of the pilot to his craft's runways when the covering is removed.
The latter two installations were designed to provide compliance with MIL-STD-850, Aircrew Station Vision Requirements for Military Aircraft. Similar standards were met during the development of the SST, Concorde, and other commercial transports. For next generation hypersonic, transatmospheric space vehicles and high Mach number military fighter craft, the above solutions to vision satisfaction problems are not applicable. High aerodynamic loads, thermodynamic considerations and weight penalties associated with transparencies in structure negate the most basic of considerations that must be made.
Alternatives to direct view systems include periscopes, radar, television cameras, focal plane sensors and others, none of which provides the "feel" required by pilots for guiding their craft at up to 200 miles an hour onto concrete runways only a few craft lengths in width.
In response to the above-discussed problems, S. Wurst and K. Matsunaga developed a novel Vision Augmentation System, Ser. No. 522,487, assigned to Rockwell International Corporation, hereby incorporated by reference, which discloses a vision system comprising a transparency, an adjustable external mirror, means for positioning the external mirror, and a cockpit mirror means. The external mirror is positionable at a stowed position adjacent the transparency which is constructed in a portion of the fuselage of the aircraft. In that stowed position the external mirror is substantially flush with the outer skin of the fuselage to maintain the aerodynamic integrity of the aircraft during high speed flight. The external mirror is positionable at least one deployed position for reflecting light received from a field of view exterior to the aircraft, during low speeds of travel. The cockpit mirror means is located internal the aircraft for receiving light reflected from the external mirror and through the transparency when the external mirror is deployed. The cockpit mirror means is constructed and arranged to redirect the reflected light toward a crew member of the aircraft, thus providing a real-time, three-dimensional view from the vantage of an "apparent eye" position located aft of the external mirror. Thus, the vision augmentation system preserves depth perception cues.
During the course of the prosecution of the Wurst et al case, present Applicants have studied avenues for minimizing the external mirror size. Reduction in this mirror size is desired for its resulting decreased weight and aerodynamic drag.